I would increase brightness or gamma to make things a bit more visible. Like Nerpson said, too much dirty lens, I'd even remove it completely. Also on the second picture, depth of field looks unnatural - when camera is very close to target object a big amount of blur will work, otherwise rather keep small amount of it at bigger distances. Also a tiny tip: try tilting the camera to left a little bit.

Yep I am a n00b... It was easy to increase the exposure.
The parameter Brightness in FxColors does not give good results, but the parameter Exposure in ToneMapping looks much better.http://imgur.com/TSKkwY1
I don't understand everything yet... I am just playing with the parameters...